Pump with floating end plates



Feb. 14, 1961 M.,G. MCLEAN 2,971,469

PUMP WITH FLOATING END PLATES Filed Sept. 14. 1959 2 Sheets-Sheet 1 15/ 2 14 12 10 r (I M a4 a? If? N /2 Jfium mm W u 56 56 Q 40 I t 30 fa? I MueeAy @M /EA 34 46 INVENTOR.

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.Hirems, Jd/Ecw, RUSSELL jdee/x Feb. 14, 1961 MG. MOLEAN PUMP WITH momma END PLATES 2 Sheets-Sheet 2 Filed Sept. 14. 1959 PUNIP WITH FLOATING END PLATES Murray G. McLean, North Tustin, Calif., assignor to Jabsco Pump Company, Costa Mesa, Calif., a corporation of California Filed Sept. 14, 1959, Ser. No. 839,955 '1 Claim. (Cl. 103-417) The present invention relates in general to pumps and, more particularly, to a pump of the type which includes an impeller having elastomeric vanes adapted to be bent by a cam in the vicinity of theinlet and outlet ports of the pump to produce a pumping action, a primary object of the invention being to provide a pump of this type having axially floating end plates which are spring biased into slidable sealing engagement with the ends of the impeller.

More specifically, the invention contemplates a pump of the type whichincludes: housing means having an axis and providedtherein with an impeller chamber and circumferentially spaced inlet and outlet ports in communication with the impeller chamber, the impeller chamber rotatable about the axis of the housing means; and an impeller in the impeller chamber and keyed to the shaft so as to rotate therewith, the impellsr having bendable elastomeric vanes slidably engaging the peripheral wall of the impeller chamber and being bent by the cam portion of such peripheral wall in the vicinity of the inlet and outlet ports so as to draw fluid in through the inlet port and expel such fluid through the outlet port in the manner characteristic of pumps of this type.

As previously indicated, the primary object of the invention is to provide a pump of the foregoing nature having axially floating end plates respectively biased into slidable sealing engagement with the ends of the impeller by spring means respectively engaging the end plates. With this construction, the end plates are capable of moving axially inwardly toward each other to compensate for wear of the impeller, and are capable of moving axially outwardly away from each other to compensate for any elongation of the impeller in use. Such elongation of the impeller may result, for example, from the action of the fluid being pumped on the elastomeric material forming the impeller, or at least the vanes thereof.

An important object of the invention is to provide end plates having outer peripheries in axially slidable engagement withtthe peripheral wall of the impeller chamber, at least one of the end plates being annular and having an inner periphery in axially slidable engagement with the shaft so that the shaft may project through such end plate to the exterior of the housing means. With this construction, the outer peripheries of the end plates conform in configuration to the peripheral wall of the impeller chamber. Since the peripheral wall of the impeller chamber is noncircular relative to the axis of the housing means, the interengagement between the peripheral wall of the impeller chamber and the outer peripherts of the axially floating end plates results in keying of the end plates to the housing means against rotation. Thus, no

Another object is to provide end plates including outer at l,

seals on their outer peripheries which are in fluid-tight engagement with the peripheral wall of the impeller chamber, and to provide the end plate through which the shaft extends with an inner seal on its inner periphery which is in fluid-tight engagement with the shaft.

A further object is to provide a construction wherein the shaft extends through one or both end plates, each end plate through which the shaft extends having on its inner periphery an inner seal in fluid-tight engagement with the shaft.

Still another object is to provide a pump wherein the spring means for biasing the end plates into engagement with the ends of the impeller are either annular springs acting on the entire end plates, or are springs acting on the end plates in the vicinities of the outlet port only.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident in the light of this disclosure, may be attained with the exemplary embodiments of the invention described in detail hereinafter and illustrated in the accompanying drawings, wherein:

Fig. l is a longitudinal sectional view of one embodiment of the pump of the invention, Fig. 1 being taken along the arrowed line 1-1 of Fig. 2;

Fig. 2 is a transverse sectional view taken along the arrowed line 2-2 of Fig. 1;

Fig. 3 is a longitudinal sectional view of another embodiment of the pump of the invention, Fig. 3 being taken along the arrowed line 33 of Fig. 4; and

Fig. 4 is a transverse sectional view taken along the arrowed line 44 of Fig. 3.

Referring first to Figs. 1 and 2 of the drawings, the pump embodiment of the invention which is illustrated therein is designated generally by the numeral 10 and includes a housing means 12 comprising a housing 14 and a cam 16. The housing 14 is provided with a cylindrical bore 18 and the cam 16 is a crescent-shaped cam disposed in the bore 18 on one side thereof and suitably secured to the housing, as by a screw 20. The peripheral wall of the bore 13 and the internal surface of the cam 16 define the peripheral wall of an impeller chamber 22 which is noncircular relative to the axis 24 of the housing 14, the axis of the housing being regarded as the axis of the cylindrical bore 13. The portion of the peripheral wall of the impeller chamber 22 which is defined by the internal surface of the cam 16 has a circumferentially varying radius relative to the axis 24, which radius is a minimum between inlet and outlet ports 26 and 28 formed in the housing 14 and the cam 16 and communicating with the impeller chamber.

Extending into the impeller chamber 22 and rotatable about the axis 24 is a shaft 30, shown as the shaft of an electric motor 32 on which the housing 14 is mounted. However, this construction may be varied without departing from the spirit of the invention.

Disposed in the impeller chamber 22 and keyed to the shaft 3% is an impeller 34 having vanes 36 slidably engaging the peripheral wall of the impeller chamber, at least the vanes 35, and preferably the entire impeller 34, being formed of an elastomeric material. With this construction, the vanes 36 are bent by the cam 16 as the impeller 34 rotates to discharge fluid from the intervane spacesinto the outlet port 28, the vanes straightening adjacent the inlet port 26 to draw fluid into the intervane spaces through such port. This action is characteristic of a pump of the type under consideration so that a further description thereof is unnecessary.

In the construction illustrated, the impeller 34 is molded onto one end of a sleeve 38 which is telescoped over the shaft 30, such sleeve being provided with an internally struck key 46 which engages a flat 42 on the shaft 30 to 3 transmit torque from the shaft to the impeller. One end of the sleeve 38 projects beyond the impeller 34 toward themotor 32 and is engaged by a shaft seal 44 carried by the housing 14. No shaft seal is necessary on the opposite side of the impeller 34 since the sleeve 38 terurinates within the impeller. a

The ends of the impeller v34 are in slidable engagement'with end plates or wear plates/l6 and 48 having outer peripheries in axially slidable engagement with the peripheral wall of the impeller chamber 22, the configuration of the outer peripheries of the end plates be ing complementary to that of the peripherial wall of the impeller chamber. The end plates 46 and 48 are provided in their outer peripheries with annular grooves containing annular seals, illustrated as O-rings 50, which provide fluid-tight seals between the outer peripheries of the end plates and .the peripheral wall of the impeller chamber 22. In the embodiment under consideration, the end plate 48 is annular and has its inner periphery in engagement with the shaft 30, or, more accurately, in engagement with the sleeve 38 on the shaft, which sleeve may be regarded as constituting a part of the shaft insofar as the relationship of the end plate 48 thereto is concerned. The end plate 48 is provided in its inner periphery with a groove containing an inner seal, such as an O-ring 52, which provides a fluid-tight seal between the end plate 48 and the sleeve 38.

Compression springs 54 and 56 seated against the housing 14 and against the respective end plates 46 and 48 bias the end plates into fluid-tight engagement with the respective ends of the impeller 34. In the embodiment under consideration, the springs 54 and 56 are coil springs located adjacent the outlet port 28 to resist the internal pressure between the end plates 46 and 48 adjacent this port. Springs acting on the end plates 46 and 48 other than adjacent the outlet port 28 are unnecessary since the internal pressure at such other points is a negative pressure tending to draw the end plates together.

As will be apparent, the spring loaded end plates 46 and 48 compensate for axial wear of the impeller 34 and, more important, they compensate for any axial expansion of the impeller. For example, axial expansion of the impeller 34 due to swelling of the elastomeric material of which it is formed may be considerable with certain elastomeric materials when pumping certain fluids. Also, the use of the spring loaded end plates 46 and 48 eliminates any necessity for close axial tolerances in manufacture since they have a compensating effect.

An important feature of the invention resides in placing the end plates 46 and 48 within the impeller chamber 22 so that the outer peripheries of the end plates are in axially slidable engagement with the peripheral wall of the impeller chamber. Since the peripheral wall of the impeller chamber is noncircular, with reference to the axis 24, the outer peripheries of the end plates 46 and 48 are also noncircular relative to such axis, with the result that the end plates are inherently keyed against rotation relative to the housing means 12 about the axis 24. Thus, no supplementary keying means for the end plates 46 and 48 is necessary.

Turning now to Figs. 3 and 4 of the drawings, the pump embodiment of the invention illustrated therein is designated generally by the numeral 119 and includes a housing means 112 comprising a housing 114- and a cam 116. In this case, the cam 116 is an integral part of an annular liner 117 disposed in a cylindrical bore 118 in the housing 114, the liner 117 being held in place by a screw 120 threaded into the housing. The liner 117 provides an impeller chamber 122, the portion of the peripheral wall of the impeller chamber which is defined by the cam 116 having a circumferentially varying radius relative to the axis 124 of the housing 114,

which axis is regarded as being the axis of the cylindrical bore 118. The housing 114 is provided with inlet and outlet ports 126 and 128 communicating with the impeller chamber 122 on opposite sides of the minimum radius of the peripheral wall of the impeller chamber.

Extending through the housing 114 is a shaft 130 rotatable about the axis 124 in bearings 133 carried by the housing. Within the impeller chamber 122 and keyed to the shaft 130 is an impeller 134 having vanes 136 slidably engaging the peripheral wall of the impeller chamber, at least the vanes 136, and preferably the entire impeller 134, being formed of an elastomeric ma terial so that the vanes are capable of being bent by the cam 116 to produce the characteristic pumping action hereinbefore described. In the particular construction illustrated, the impeller 134 is molded on a sleeve 138 which is keyed to the shaft 130 by a key 140.

The respective ends of the impeller 134 slidably engage axially movable end plates 146 and.148, these end plates havingouter peripheries complementary to the peripheral wall of the impeller chamber 122 and having in their outer peripheries annular grooves containing annular seals, such as O-rings 150, which provide fluid-tight seals between the outer peripheries of the end plates and the peripheral wall of the impeller chamber. In the pump 110, both of the end plates 146 and 148 are annular and have circular inner peripheries provided therein with annular grooves carrying inner annular seals, such as O-rings 152, for maintaining fluid-tight seals between the inner peripheries of the end plates and the shaft 130.

It will be apparent that since the impeller chamber 122 is noncircular relative to the axis 124, interengagement between the outer peripheries of the end plates 146 and 148 and the peripheral wall of the impeller chamber prevents rotation of the end plates. Thus, no supplementary keying means is necessary.

The end plates 146 and 148 are biased axially into slidable engagement with the ends of the impeller 134 by annular springs 154 and 156 acting between the respective end plates and the housing 114. In the particular construction shown, the springs 154 and 156 are Belleville washers.

Although exemplary embodiments of the invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claim which follows:

I claim:

In a pump, the combination of: housing means having an axis and provided therein with an impeller chamber having a peripheral wall, one portion of said peripheral wall of said impeller chamber comprising a cylindrical surface coaxial with said axis, the other, remaining portion of said peripheral wall of said impeller chamber comprising a radially inwardly concave, generally arcuate and generally chordal surface located on one side of said axis and located closer to said axis than said cylindrical surface, said housing means being provided therein with circumferentially spaced inlet and outlet ports in communication with said impeller chamber adjacent the respective ends of said generally chordal surface; a shaft in said impeller chamber and coaxial with and rotatable about said axis; an impeller in said impeller chamber and fixed on said shaft for rotation therewith, said impeller having axially spaced ends and having circumferentially bendable, elastomeric vanes sequentially slidably engageable with said cylindrical surface and said generally chordal surface of said peripheral wall of said impeller chamber; end plates in said impeller chamber and having peripheral walls in engagement with said peripheral wall of said impeller chamber, one portion of said peripheral wall of each of said end plates comprising a cylindrical surface coaxial with said axis and engaging said cylindrical surface of said peripheral wall of said impeller chamber, the other, remaining portion of said peripheral "wall of each of said end plates comprising a radially outwardly convex, generally arcuate and generally chordal surface engaging said generally chordal surface of said peripheral wall of said impeller chamber, said end plates being slidable relative to said peripheral wall of said impeller chamber in directions parallel to said axis and into slidable engagement with said ends of said impeller, respectively, at least one of said end plates having a cylindrical opening therethrough which is coaxial with said axis and the peripheral wall of which is in engagement with said shaft; outer seals carried by said peripheral walls ofsaid end plates, respectively, and engaging said peripheral wall of said impeller chamber; an inner seal carried by said peripheral wall of said cylindrical opening in said one end plate and engaging said shaft; and spring means engaging said housing means and respectively engaging said end plates and bias- 6 ing said end plates into engagement with said ends, respectively, of said impeller.

References Cited in the file of this patent UNITED STATES PATENTS 164,147 Conver June 8, 1875 1,996,875 McCann Apr. 9, 1935 2,052,474 Johnson Aug. 25, 1936 2,521,420 Spotz Sept. 5, 1950 2,569,717 Holl Oct. 2, 1951 2,648,287 Thoren et al Aug. 11, 1953 2,858,769 Doble Nov. 4, 1958 FOREIGN PATENTS 337,605 Switzerland May 30, 1959 ,1,181,786 France Jan. 12, 1959 

